Section 2 – Geometric Sequences and Series Chapter 12 Section 2 – Geometric Sequences and Series

Geometric Sequence A geometric sequence is a sequence of terms that are multiplied by a ratio to get to consecutive terms. This ratio is called the common ratio and is denoted with an r. For example: 3, 1, 1/3, 1/9,... is a geometric sequence with a common ratio of r = 1/3

The nth term The nth term of a geometric sequence with first term a1 and common ratio r is given by an = a1(rn-1) The sum of the first n terms of a finite geometric series is given by the formula: Sn = (a1 - a1rn)/(1-r)

Examples EX 1: Find the sum of the first ten terms of the geometric series: 16 – 48 + 144 – 432 + ...

Assignment Chapter 12, Section 2 pgs 771-773 #16-32E,42,48